Starting to see "Square" type devices attached to smart phones that allow individuals or small merchants to accept payments. It is my understanding (from TV ads) that when you sign up for Square you agree to allow Square to charge you (the merchant) a percentage of the transaction.

I have just heard of a local merchant who is charging the customer a percentage of the transaction as a fee for a service the merchant has contracted for.

This seems to be similar to those merchants who charge debit card customers a percentage of the transaction for them to accept the card.

Isn't this a violation of Visa rules?

This is from the Square website :
"Can I pass the transaction fee onto my customers?
When you price the items you sell, you are free to incorporate any costs incurred in your business operations. However, you cannot itemize Square's transaction fee in order to pass this cost on to your customers. Applying a surcharge is against the Commercial Entity Agreement and agreement with the payment processing network that you agree to as a Square account holder."

Hope this helps some,
Russ

Yes, thank you.